oracle join on 数据过滤问题

因为在FOR .. IN () LOOP 游标中使用 所以不能采用下面的查询语句做游标

代码如下:
select a.f_username
from
(
SELECT /*+parallel(gu,4)*/distinct gu.f_username
FROM t_base_succprouser gu
where gu.f_expectenddate > (select trunc(sysdate,'Y')FROM DUAL)
and gu.f_lotid=1
and gu.f_playid=4
and gu.f_paymoney>=1500
) A
left join
(
select
from t_base_vip_customes
and ((vu.f_passeddate is null ) or (vu.f_passeddate > trunc(sysdate,'Y') ))
and ((vu.f_lotid is null ) or (vu.f_lotid=1))
and ((vu.f_playid is null ) or (vu.f_playid=4))
and ((vu.f_condtionid is null ) or (vu.f_condtionid=3))
)B
on A.f_username=B.f_usernam
where b.f_username is null

采用下面的语句 只能查出部分用户
代码如下:
SELECT /*+parallel(gu,4)*/distinct gu.f_username
FROM t_base_succprouser gu
left join t_base_vip_customes VU on gu.f_username=vu.f_username
gu.f_expectenddate > (select trunc(sysdate,'Y')FROM DUAL)
and gu.f_lotid=rec_viplotplay.f_lotid
and gu.f_playid=rec_viplotPlay.f_Playid
and gu.f_paymoney>=rec_viplotPlay.F_Conditon_ValuesA
and ((vu.f_passeddate is null ) or (vu.f_passeddate > trunc(sysdate,'Y') ))
and ((vu.f_lotid is null ) or (vu.f_lotid=rec_viplotplay.f_lotid))
and ((vu.f_playid is null ) or (vu.f_playid=rec_viplotPlay.f_Playid))
and ((vu.f_condtionid is null ) or (vu.f_condtionid=rec_viplotPlay.F_CondtionID))
and vu.f_username is null

执行计划：
代码如下:
SELECT STATEMENT, GOAL = ALL_ROWS
HASH UNIQUE
NESTED LOOPS OUTER
PARTITION RANGE ALL
TABLE ACCESS FULL Object name=T_BASE_SUCCPROUSER
VIEW
FILTER
TABLE ACCESS FULL Object name=T_BASE_VIP_CUSTOMES
FAST DUAL

后来改成了下面就能全部查出来了
代码如下:
SELECT /*+parallel(gu,4)*/distinct gu.f_username
FROM t_base_succprouser gu
left join t_base_vip_customes VU on gu.f_username=vu.f_username
and ((vu.f_passeddate is null ) or (vu.f_passeddate > trunc(sysdate,'Y') ))
and ((vu.f_lotid is null ) or (vu.f_lotid=rec_viplotplay.f_lotid))
and ((vu.f_playid is null ) or (vu.f_playid=rec_viplotPlay.f_Playid))
and ((vu.f_condtionid is null ) or (vu.f_condtionid=rec_viplotPlay.F_CondtionID))

where gu.f_expectenddate > (select trunc(sysdate,'Y')FROM DUAL)
and gu.f_lotid=rec_viplotplay.f_lotid
and gu.f_playid=rec_viplotPlay.f_Playid
and gu.f_paymoney>=rec_viplotPlay.F_Conditon_ValuesA
and vu.f_username is null
执行计划：
SELECT STATEMENT, GOAL = ALL_ROWS
HASH UNIQUE
FILTER
NESTED LOOPS OUTER
TABLE ACCESS BY GLOBAL INDEX ROWID Object name=T_BASE_SUCCPROUSER
INDEX RANGE SCAN Object name=IX_BASE_PROUSER_LOWEX
FAST DUAL
VIEW
TABLE ACCESS FULL Object name=T_BASE_VIP_CUSTOMES

oracle 不懂先把数据给过滤掉然后在来连接吗？ 太笨了！而且这样把符合条件的数据也过滤掉了